Pre-treatment bone mineral density (BMD) and the benefit of pharmacologic treatment on fracture risk and BMD change: analysis from the FNIH-ASBMR SABRE project.

Some osteoporosis drug trials have suggested that treatment is more effective in those with low bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA). This study used data from a large set of randomised controlled trials (RCTs) to determine whether the anti-fracture efficacy of treatments differs according to baseline BMD. We used individual patient data from 25 RCTs (103 086 subjects) of osteoporosis medications collected as part of the FNIH-ASBMR SABRE project. Participants were stratified into femoral neck (FN) BMD T-score subgroups (≤ -2.5, > -2.5). We used Cox proportional hazard regression to estimate treatment effect for clinical fracture outcomes and logistic regression for the radiographic vertebral fracture outcome. We also performed analyses based on BMD quintiles. Overall, 42% had a FN BMD T-score ≤ -2.5. Treatment with anti-osteoporosis drugs led to significant reductions in fractures in both T-score ≤ -2.5 and > -2.5 subgroups. Compared to those with FN BMD T-score > -2.5, the risk reduction for each fracture outcome was greater in those with T-score ≤ -2.5, but only the all fracture outcome reached statistical significance (interaction p = 0.001). Results were similar when limited to bisphosphonate trials. In the quintile analysis, there was significant anti-fracture efficacy across all quintiles for vertebral fractures and with greater effects on fracture risk reduction for non-vertebral, all and all clinical fractures in the lower BMD quintiles (all interaction p ≤ 0.03). In summary, anti-osteoporotic medications reduced the risk of fractures regardless of baseline BMD. Significant fracture risk reduction with treatment for 4 of the 5 fracture endpoints was seen in participants with T-scores above -2.5, though effects tended to be larger and more significant in those with baseline T-scores <-2.5.

It is important to know whether our treatments for osteoporosis are effective at reducing the risk of fracture no matter what the bone mineral density (BMD) before starting treatment. This study used data from many clinical trials to determine whether the anti-fracture efficacy of treatments differs according to baseline BMD. We found that anti-osteoporotic medications reduced the risk of fractures regardless of baseline BMD, though effects tended to be larger and more significant in those with lower BMD scores.

Design of the COMEBACK and BACKHOME Studies, Longitudinal Cohorts for Comprehensive Deep Phenotyping of Adults with Chronic Low-Back Pain (cLBP): a part of the BACPAC Research Program.

Objective: The University of California, San Francisco (UCSF) Core Center for Patient-centric, Mechanistic Phenotyping in Chronic Low Back Pain (REACH) is one of the three NIH Back Pain Consortium (BACPAC) Research Programs Mechanistic Research Centers (MRCs). The goal of UCSF REACH is to define cLBP phenotypes and pain mechanisms that can lead to effective, personalized treatments for patients across the population. The primary objective of this research project is to address the critical need for new diagnostic and prognostic markers, and associated patient classification protocols for chronic low back pain (cLBP) treatment. Design: To meet this objective, REACH is conducting two large investigator-initiated translational research cohort studies called: The Longitudinal Clinical Cohort for Comprehensive Deep Phenotyping of Chronic Low-Back Pain (cLBP) Adults Study (comeBACK) and the Chronic Low-Back Pain (cLBP) in Adults Study (BACKHOME). Setting: comeBACK is a longitudinal multicenter in-person observational study of 450 adults with chronic low back pain designed to perform comprehensive deep phenotyping. While, the BACKHOME study is a site-less longitudinal observational e-cohort of approximately 3000 U.S. adults with cLBP. To our knowledge, BACKHOME is the largest prospective remote registry of nationwide adults with cLBP. Methods: Both the comeBACK and BACKHOME studies are collecting a robust and comprehensive set of risk factors, outcomes, and covariates in order to perform deep phenotyping of cLBP patients based on combined biopsychosocial variables to: define cLBP subtypes, establish phenotyping tools for routine clinical evaluation, and lead to improved cLBP outcomes in the future. The data from both studies will be used to establish techniques to develop a patient-centric definition of treatment success and to analyze cLBP patient traits to define clinically useful cLBP phenotypes, using a combination of traditional data analyses and deep learning methods. Conclusions: These 2 pivotal studies, in conjunction with the ancillary studies being performed in both comeBACK and BACKHOME, and the other BACPAC-consortium research projects, we will be able to address a number of diagnostic and therapeutic issues in this complex and diverse patient population with cLBP. These studies will help clarify biopsychosocial mechanisms of cLBP with the aim to provide a foundation to improve the evaluation of treatment effectiveness and to spur new avenues of therapeutic research, including personalized outcome measures that constitute a clinically meaningful treatment effect for individual cLBP patients.

Predictors of response in PROMIS-global in a chronic low back pain specialty clinic: STarTBack and chronic overlapping pain conditions.

BACKGROUND: Tools, such as the STarTBack Screening Tool (SBT), have been developed to identify risks of progressing to chronic disability in low back pain (LBP) patients in the primary care population. However, less is known about predictors of change in function after treatment in the specialty care population. OBJECTIVE: We pursued a retrospective observational cohort study involving LBP patients seen in a multidisciplinary specialty clinic to assess which features can predict change in function at follow-up. METHODS: The SBT was administered at initial visit, and a variety of patient characteristics were available in the chart including the presence of chronic overlapping pain conditions (COPCs). Patient Reported Outcomes Measurement Information System-10 (PROMIS-10) global physical health (PH) and global mental health (MH) were measured at baseline and at pragmatic time points during follow-up. Linear regression was used to estimate adjusted associations between available features and changes in PROMIS scores. RESULTS: 241 patients were followed for a mean of 17.0 ± 7.5 months. Mean baseline pain was 6.7 (SD 2.1), PROMIS-10 global MH score was 44.8 (SD 9.3), and PH score was 39.4 (SD 8.6). 29.7% were low-risk on the SBT, 41.8% were medium-risk, and 28.5% were high-risk. Mean change in MH and PH scores from baseline to the follow-up questionnaire were 0.86 (SD 8.11) and 2.39 (SD 7.52), respectively. Compared to low-risk patients, high-risk patients had a mean 4.35 points greater improvement in their MH score (p= 0.004) and a mean 3.54 points greater improvement in PH score (p= 0.006). Fewer COPCs also predicted greater improvement in MH and PH. CONCLUSIONS: SBT and the presence of COPC, which can be assessed at initial presentation to a specialty clinic, can predict change in PROMIS following treatment. Effort is needed to identify other factors that can help predict change in function after treatment in the specialty care setting.

Influence of age on the efficacy of pharmacologic treatments on fracture risk reduction and increases in BMD: RCT results from the FNIH-ASBMR-SABRE project.

There is a common belief that antiosteoporosis medications are less effective in older adults. This study used data from randomized controlled trials (RCTs) to determine whether the anti-fracture efficacy of treatments and their effects on BMD differ in people ≥70 compared to those <70 yr. We used individual patient data from 23 RCTs of osteoporosis medications collected as part of the FNIH-ASBMR SABRE project. We assessed the following fractures: radiographic vertebral, non-vertebral, hip, all clinical, and all fractures. We used Cox proportional hazard regression to estimate treatment effect for clinical fracture outcomes, logistic regression for the radiographic vertebral fracture outcome, and linear regression to estimate treatment effect on 24-mo change in hip and spine BMD in each age subgroup. The analysis included 123 164 (99% female) participants; 43% being ≥70 yr. Treatment with anti-osteoporosis drugs significantly and similarly reduced fractures in both subgroups (eg, odds ratio [OR] = 0.47 and 0.51 for vertebral fractures in those below and above 70 yr, interaction P = .19; hazard ratio [HR] for all fractures: 0.72 vs 0.70, interaction P = .20). Results were similar when limited to bisphosphonate trials with the exception of hip fracture risk reduction which was somewhat greater in those <70 (HR = 0.44) vs ≥70 (HR = 0.79) yr (interaction P = .02). Allocation to anti-osteoporotic drugs resulted in significantly greater increases in hip and spine BMD at 24 mo in those ≥70 compared to those <70 yr. In summary, anti-osteoporotic medications similarly reduced the risk of fractures regardless of age, and the few small differences in fracture risk reduction by age were of uncertain clinical significance.

Medications used for osteoporosis maybe are less effective in older adults. This study used data from clinical trials to determine whether these medications work equally well in reducing the risk of fractures in people ≥70 compared to those <70 yr. The analysis included 123 164 participants with data from 23 trials. Treatment with anti-osteoporosis drugs significantly reduced fractures in both groups in a similar way. The BMD increased more in the older group.

Bisphosphonate Use and Risk of Atypical Femoral Fractures: A Danish Case Cohort Study with Blinded Radiographic Review.

CONTEXT: Prolonged bisphosphonate (BP) treatment for osteoporosis prevents hip and other fractures but causes atypical femoral fractures (AFF). OBJECTIVE: To establish the relationship between patterns of BP use and the risk of AFF and hip fractures. Other potential risk factors for AFF were also examined. DESIGN: Population-based case-cohort study. SETTING: The Danish National Healthcare system maintains longitudinal records of medication use, healthcare utilization, and x-ray images. PARTICIPANTS: Among all 1.9 million Danish adults ≥50, those with subtrochanteric or femoral shaft fractures between 2010-2015 (n = 4,973) were identified and compared to a random sample (n = 37,021). PREDICTORS: Bisphosphonate use was collected from 1995-2015. MAIN OUTCOME MEASURES: Fracture radiographs (n = 4,769) were reviewed by blinded study radiologists to identify AFFs (n = 181) using established criteria. Traditional hip fractures in the random sample (n = 691) were identified by ICD-10. RESULTS: Compared to <1 year of BP use, 5-7 years of use was associated with a 7-fold increase in AFF [adjusted HR = 7.29 (CI: 3.07,17.30)]; the risk of AFF fell quickly after discontinuation. The 5-year number-needed-to-harm for one AFF was 1,424, while the 5-year number-needed-to-treat to prevent one hip fracture was 56. Glucocorticoid and proton pump inhibitor use were independently associated with increased AFF risk. Thirty-one percent of those with AFF had no BP exposure. CONCLUSIONS: The risk of AFF increases with duration of BP use but the beneficial effects of BP therapy in adults ≥50 dramatically exceed this increased risk. Nearly one-third of those with AFF have no BP exposure.

Intestinal Calcium Absorption Decreases After Laparoscopic Sleeve Gastrectomy Despite Optimization of Vitamin D Status.

CONTEXT: Laparoscopic sleeve gastrectomy (LSG), now the most commonly performed bariatric operation, is a highly effective treatment for obesity. While Roux-en-Y gastric bypass is known to impair intestinal fractional calcium absorption (FCA) and negatively affect bone metabolism, LSG's effects on calcium homeostasis and bone health have not been well characterized. OBJECTIVE: We determined the effect of LSG on FCA, while maintaining robust 25-hydroxyvitamin D (25OHD) levels and recommended calcium intake. DESIGN, SETTING, PARTICIPANTS: Prospective pre-post observational cohort study of 35 women and men with severe obesity undergoing LSG. MAIN OUTCOMES: FCA was measured preoperatively and 6 months postoperatively with a gold-standard dual stable isotope method. Other measures included calciotropic hormones, bone turnover markers, and bone mineral density (BMD) by dual-energy X-ray absorptiometry and quantitative computed tomography. RESULTS: Mean ± SD FCA decreased from 31.4 ± 15.4% preoperatively to 16.1 ± 12.3% postoperatively (P < 0.01), while median (interquartile range) 25OHD levels were 39 (32-46) ng/mL and 36 (30-46) ng/mL, respectively. Concurrently, median 1,25-dihydroxyvitamin D level increased from 60 (50-82) pg/mL to 86 (72-107) pg/mL (P < 0.01), without significant changes in parathyroid hormone or 24-hour urinary calcium levels. Bone turnover marker levels increased substantially, and areal BMD decreased at the proximal femur. Those with lower postoperative FCA had greater areal BMD loss at the total hip (ρ = 0.45, P < 0.01). CONCLUSIONS: FCA decreases after LSG, with a concurrent rise in bone turnover marker levels and decline in BMD, despite robust 25OHD levels and with recommended calcium intake. Decline in FCA could contribute to negative skeletal effects following LSG.

Guidance for the diagnosis and treatment of hypolipidemia disorders.

The Abetalipoproteinemia and Related Disorders Foundation was established in 2019 to provide guidance and support for the life-long management of inherited hypocholesterolemia disorders. Our mission is "to improve the lives of individuals and families affected by abetalipoproteinemia and related disorders". This review explains the molecular mechanisms behind the monogenic hypobetalipoproteinemia disorders and details their specific pathophysiology, clinical presentation and management throughout the lifespan. In this review, we focus on abetalipoproteinemia, homozygous hypobetalipoproteinemia and chylomicron retention disease; rare genetic conditions that manifest early in life and cause severe complications without appropriate treatment. Absent to low plasma lipid levels, in particular cholesterol and triglyceride, along with malabsorption of fat and fat-soluble vitamins are characteristic features of these diseases. We summarize the genetic basis of these disorders, provide guidance in their diagnosis and suggest treatment regimens including high dose fat-soluble vitamins as therapeutics. A section on preconception counseling and other special considerations pertaining to pregnancy is included. This information may be useful for patients, caregivers, physicians and insurance agencies involved in the management and support of affected individuals.

Diabetes Mellitus and the Benefit of Antiresorptive Therapy on Fracture Risk.

Type 2 diabetes (T2D) is associated with increased risk of fractures. However, it is unclear whether current osteoporosis treatments reduce fractures in individuals with diabetes. The aim of the study was to determine whether presence of T2D influences the efficacy of antiresorptive treatment for osteoporosis using the Foundation for the National Institutes of Health (FNIH)-American Society for Bone and Mineral Research (ASBMR)-Study to Advance Bone Mineral Density (BMD) as a Regulatory Endpoint (SABRE) cohort, which includes individual patient data from randomized trials of osteoporosis therapies. In this study we included 96,385 subjects, 6.8% of whom had T2D, from nine bisphosphonate trials, two selective estrogen receptor modulator (SERM) trials, two trials of menopausal hormone therapy, one denosumab trial, and one odanacatib trial. We used Cox regression to obtain the treatment hazard ratio (HR) for incident nonvertebral, hip, and all fractures and logistic regression to obtain the treatment odds ratio (OR) for incident morphometric vertebral fractures, separately for T2D and non-DM. We used linear regression to estimate the effect of treatment on 2-year change in BMD (n = 49,099) and 3-month to 12-month change in bone turnover markers (n = 12,701) by diabetes status. In all analyses, we assessed the interaction between treatment and diabetes status. In pooled analyses of all 15 trials, we found that diabetes did not impact treatment efficacy, with similar reductions in vertebral, nonvertebral, all, and hip fractures, increases in total hip and femoral neck BMD, and reductions in serum C-terminal cross-linking telopeptide (CTX), urinary N-telopeptide of type I collagen/creatinine (NTX/Cr) and procollagen type 1 N propeptide (P1NP) (all interactions p > 0.05). We found similar results for the pooled analysis of bisphosphonate trials. However, when we considered trials individually, we found a few interactions within individual studies between diabetes status and the effects of denosumab and odanacatib on fracture risk, change in BMD or bone turnover markers (BTMs). In sum, these results provide strong evidence that bisphosphonates and most licensed antiresorptive drugs are effective at reducing fracture risk and increasing BMD irrespective of diabetes status. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Supplemental Vitamin D and Incident Fractures in Midlife and Older Adults.

BACKGROUND: Vitamin D supplements are widely recommended for bone health in the general population, but data on whether they prevent fractures have been inconsistent. METHODS: In an ancillary study of the Vitamin D and Omega-3 Trial (VITAL), we tested whether supplemental vitamin D3 would result in a lower risk of fractures than placebo. VITAL was a two-by-two factorial, randomized, controlled trial that investigated whether supplemental vitamin D3 (2000 IU per day), n-3 fatty acids (1 g per day), or both would prevent cancer and cardiovascular disease in men 50 years of age or older and women 55 years of age or older in the United States. Participants were not recruited on the basis of vitamin D deficiency, low bone mass, or osteoporosis. Incident fractures were reported by participants on annual questionnaires and adjudicated by centralized medical-record review. The primary end points were incident total, nonvertebral, and hip fractures. Proportional-hazards models were used to estimate the treatment effect in intention-to-treat analyses. RESULTS: Among 25,871 participants (50.6% women [13,085 of 25,871] and 20.2% Black [5106 of 25,304]), we confirmed 1991 incident fractures in 1551 participants over a median follow-up of 5.3 years. Supplemental vitamin D3, as compared with placebo, did not have a significant effect on total fractures (which occurred in 769 of 12,927 participants in the vitamin D group and in 782 of 12,944 participants in the placebo group; hazard ratio, 0.98; 95% confidence interval [CI], 0.89 to 1.08; P = 0.70), nonvertebral fractures (hazard ratio, 0.97; 95% CI, 0.87 to 1.07; P = 0.50), or hip fractures (hazard ratio, 1.01; 95% CI, 0.70 to 1.47; P = 0.96). There was no modification of the treatment effect according to baseline characteristics, including age, sex, race or ethnic group, body-mass index, or serum 25-hydroxyvitamin D levels. There were no substantial between-group differences in adverse events as assessed in the parent trial. CONCLUSIONS: Vitamin D3 supplementation did not result in a significantly lower risk of fractures than placebo among generally healthy midlife and older adults who were not selected for vitamin D deficiency, low bone mass, or osteoporosis. (Funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases; VITAL ClinicalTrials.gov number, NCT01704859.).

Coronary artery calcium and bone mineral density by serial CTA: Does menopausal hormone therapy modify the association?

INTRODUCTION: Both osteoporosis and cardiovascular disease (CVD) increase in women after menopause. Estrogen deficiency is thought to be an underlying mechanism for both these conditions. METHODS: Healthy menopausal women (n = 374, age 42-58 years) underwent cardiac CT scans over four years as participants in the Kronos Early Estrogen Prevention Study (KEEPS), a randomized, controlled trial to Women randomized to either oral conjugated equine estrogens (o-CEE, n = 104), transdermal 17ß-estradiol (t-E2, n = 119) or placebo (n-115). CAC (Agatston units, AU), and BMD (mg/cm3) were measured from thoracic vertebrae at baseline and at the 4 years of the study using validated software. ANOVA and multiple linear regression analyzed the association between incident CAC or progression of CAC and BMD among the treatment groups. RESULTS: At baseline 374 women, 40 participants with CAC >0 had greater decrements in BMD than the 334 participants with CAC = 0 at baseline, The average change in BMD in o-CEE group with CAC was -9.6 ± 13.3 versus -3.1 ± 19.5 in those with zero CAC, p = 0.0018. With t-E2, BMD changed by -11.7 ± 26.2 in those with CAC versus +5.7 ± 26.2 in the zero CAC group, p ≤ 0. 0001. Similarly in the 66 participants that showed progression of CAC >1, had more BMD loss, than those with stable CAC regardless of the treatment. CONCLUSION: Progression of bone loss is reduced among women treated with o-CEE or t-E2. Progression of CAC is associated with greater BMD loss, a relationship that is differentially modified by t-E2 and o-CEE.

Apolipoprotein A5, a unique modulator of fasting and postprandial triglycerides.

The discovery of apolipoprotein A5 (APOA5) in 2001 has raised a number of intriguing questions about its role in lipid transport and triglyceride (TG) homeostasis. Genome-wide association studies have consistently identified APOA5 as a regulator of plasma TG levels, which is further supported by studies in transgenic and knockout mouse models. The present review describes recent concepts pertaining to the roles of APOA5 in TG metabolism as related to the vascular compartment, liver, adipose tissue and the gut. Recent evidence indicates that APOA5 may also affect postprandial TG metabolism through influencing chylomicron formation and transport by the intestine into the intestinal lymph. While substantial evidence supports the notion that APOA5 plays both extracellular and intracellular roles in TG homeostasis, mysteries remain on how this low-abundance, liver-derived protein may modulate TG homeostasis, including via the gut. Given the strong correlation between elevated plasma TG and cardiometabolic diseases, there is great scientific and public interest in understanding the intriguing mysteries presented by APOA5.

Low cumulative disease activity is associated with higher bone mineral density in a majority Latinx and Asian US rheumatoid arthritis cohort.

OBJECTIVE: Prior studies have found conflicting results when evaluating the association between rheumatoid arthritis (RA) disease activity and bone mineral density (BMD). Whether or not cumulative RA disease activity is associated with BMD remains unanswered. METHODS: Data were from the University of California San Francisco RA Cohort from years 2006-2018. Those with BMD measures and at least two study visits prior to BMD measure were included in the study. The association between low cumulative disease activity, as measured by DAS28ESR, with the primary outcome of femoral neck BMD was assessed using multivariable linear regression. Sensitivity analyses were performed substituting CDAI for the disease activity measure as well as total hip and lumbar spine BMD as outcomes. RESULTS: 161 participants with RA were studied. The cohort was 62.4 ± 10.2 years old and 88% female. Hispanic/Latino (N = 73, 45%) and Asian (N = 59, 37%) were the most common racial/ethnic groups in our cohort. Mean RA duration was 10.5 ± 7.3 years and 83% were ACPA positive. Low disease activity was independently associated with higher femoral neck BMD compared to the moderate/high disease activity group (ß= 0.071 [95%CI: 0.021 to 0.122], p = 0.020). The relationship between low cumulative disease activity was similar when CDAI and other BMD sites were substituted in the multivariable models. CONCLUSION: Low cumulative disease activity as measured by DAS28ESR was associated with higher femoral neck BMD, independent of traditional osteoporosis risk factors (e.g., age, sex, BMI) in a unique RA cohort. Results were similar when evaluating cumulative low CDAI and other BMD sites.

Outcomes post fragility fracture among members of an integrated healthcare organization.

This study highlights an unmet need in osteoporosis management, suggesting that beyond bone mineral density and fracture history, gender, fracture type, and age should be considered for fracture risk assessment. Following fragility fracture, men, patients with a spine or hip fracture, and those aged ≥ 65 have a higher disease burden. INTRODUCTION: The objective of this study was to characterize osteoporosis-related fracture incidence and identify predictors of subsequent fractures and mortality. METHODS: This retrospective cohort study, conducted within Kaiser Permanente Southern California, included patients aged ≥ 50 years with qualifying fractures from 1/1/2007 to 12/31/2016, identified from diagnosis/procedure codes. Rates for fracture incidence, mortality, and resource utilization in the year post-fracture are reported. Associations between index fracture types and demographic/clinical characteristics, and mortality, subsequent fracture, and rehospitalization outcomes were estimated. RESULTS: Of 63,755 eligible patients, 66.7% were ≥ 65 years and 69.1% female. Index fractures included nonhip/nonspine (64.4%), hip (25.3%), and spine (10.3%). Age-adjusted subsequent fracture rate/100 person-years was higher for those with an index spine (14.5) versus hip fracture (6.3). Hospitalization rate/100 person-years was highest for patients ≥ 65 (31.8) and for spine fractures (43.5). Men (vs women) had higher age-adjusted rates of hospitalization (19.4; 17.7), emergency room visits (73.8; 66.3), and use of rehabilitation services (31.7; 27.2). The 30-day age-adjusted mortality rate/100 person-years was 46.7, 32.4, and 15.5 for spine, hip, and nonspine/nonhip fractures. The 1-year age-adjusted mortality rate/100 person-years was 14.7 for spine and 15.6 for hip fractures. In multivariable analyses, spine and hip fractures (vs nonhip/nonspine fractures) were significant predictors of 1-year mortality, all-cause and osteoporosis-related hospitalization, and nursing home use (all P-values < 0.0001). CONCLUSION: Morbidity is high in the year following a fragility fracture and men, patients with a spine or hip fracture, and those aged ≥ 65 have a greater disease burden.

The Interaction of Acute-Phase Reaction and Efficacy for Osteoporosis After Zoledronic Acid: HORIZON Pivotal Fracture Trial.

Zoledronic acid (ZOL) as a yearly infusion is effective in reducing fracture risk. An acute-phase reaction (APR), consisting of flu-like symptoms within 3 days after infusion, is commonly seen. The objective of this analysis was to investigate whether APR occurrence influences drug efficacy. This analysis uses data from the 3-year randomized clinical trial, Health Outcomes and Reduced Incidence with Zoledronic Acid Once Yearly-Pivotal Fracture Trial (HORIZON-PFT). APRs were identified as adverse events within 3 days of first infusion with higher frequency in ZOL than placebo. To compare mean 3-year change in bone mineral density (BMD) in ZOL versus placebo, among women with and without APR, t tests were used. Logistic regression was used to examine the relationship between APR occurrence and odds of incident morphometric vertebral fracture. Cox regression was used to determine the risk of nonvertebral and hip fractures for women with versus without APR. Logistic and Cox models were used to determine the risk of incident fracture in ZOL versus placebo for women with and without an APR. The analysis included 3862 women in the ZOL group and 3852 in placebo, with 42.4% in ZOL versus 11.8% in placebo experiencing an APR. The difference in BMD mean change for ZOL versus placebo was similar for women with and without an APR (all p interaction >0.10). Among ZOL women, those with APR had 51% lower vertebral fracture risk than those without (odds ratio [OR] = 0.49, p < 0.001). A similar but nonsignificant trend was observed for nonvertebral and hip fracture (relative hazard [RH] = 0.82, p = 0.10; RH = 0.70, p = 0.22, respectively). There was a greater treatment-related reduction in vertebral fracture risk among women with APR (OR = 0.19) than those without (OR = 0.38) (p interaction = 0.01). Our results suggest that women starting ZOL who experience an APR will have a larger reduction in vertebral fracture risk with ZOL. © 2021 American Society for Bone and Mineral Research (ASBMR).

Validation of the Surrogate Threshold Effect for Change in Bone Mineral Density as a Surrogate Endpoint for Fracture Outcomes: The FNIH-ASBMR SABRE Project.

The surrogate threshold effect (STE) is defined as the minimum treatment effect on a surrogate that is reliably predictive of a treatment effect on the clinical outcome. It provides a framework for implementing a clinical trial with a surrogate endpoint. The aim of this study was to update our previous analysis by validating the STE for change in total hip (TH) BMD as a surrogate for fracture risk reduction; the novelty of this study was this validation. To do so, we used individual patient data from 61,415 participants in 16 RCTs that evaluated bisphosphonates (nine trials), selective estrogen receptor modulators (four trials), denosumab (one trial), odanacatib (one trial), and teriparatide (one trial) to estimate trial-specific treatment effects on TH BMD and all, vertebral, hip, and nonvertebral fractures. We then conducted a random effects meta-regression of the log relative fracture risk reduction against 24-month change in TH BMD, and computed the STE as the intersection of the upper 95% prediction limit of this regression with the line of no fracture reduction. We validated the STE by checking whether the number of fractures in each trial provided 80% power and determining what proportion of trials with BMD changes ≥ STE reported significant reductions in fracture risk. We applied this analysis to (i) the trials on which we estimated the STE; and (ii) trials on which we did not estimate the STE. We found that the STEs for all, vertebral, hip, and nonvertebral fractures were 1.83%, 1.42%, 3.18%, and 2.13%, respectively. Among trials used to estimate STE, 27 of 28 were adequately powered, showed BMD effects exceeding the STE, and showed significant reductions in fracture risk. Among the validation set of 11 trials, 10 met these criteria. Thus STE differs by fracture type and has been validated in trials not used to develop the approach. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Systems genetics analysis defines importance of TMEM43/LUMA for cardiac- and metabolic-related pathways.

Broad cellular functions and diseases including muscular dystrophy, arrhythmogenic right ventricular cardiomyopathy (ARVC5) and cancer are associated with transmembrane protein43 (TMEM43/LUMA). The study aimed to investigate biological roles of TMEM43 through genetic regulation, gene pathways and gene networks, candidate interacting genes, and up- or downstream regulators. Cardiac transcriptomes from 40 strains of recombinant inbred BXD mice and two parental strains representing murine genetic reference population (GRP) were applied for genetic correlation, functional enrichment, and coexpression network analysis using systems genetics approach. The results were validated in a newly created knock-in Tmem43-S358L mutation mouse model (Tmem43S358L) that displayed signs of cardiac dysfunction, resembling ARVC5 phenotype seen in humans. We found high Tmem43 levels among BXDs with broad variability in expression. Expression of Tmem43 highly negatively correlated with heart mass and heart rate among BXDs, whereas levels of Tmem43 highly positively correlated with plasma high-density lipoproteins (HDL). Through finding differentially expressed genes (DEGs) between Tmem43S358L mutant and wild-type (Tmem43WT) lines, 18 pathways (out of 42 found in BXDs GRP) that are involved in ARVC, hypertrophic cardiomyopathy, dilated cardiomyopathy, nonalcoholic fatty liver disease, Alzheimer's disease, Parkinson's disease, and Huntington's disease were verified. We further constructed Tmem43-mediated gene network, in which Ctnna1, Adcy6, Gnas, Ndufs6, and Uqcrc2 were significantly altered in Tmem43S358L mice versus Tmem43WT controls. Our study defined the importance of Tmem43 for cardiac- and metabolism-related pathways, suggesting that cardiovascular disease-relevant risk factors may also increase risk of metabolic and neurodegenerative diseases via TMEM43-mediated pathways.

Bisphosphonates and the risk of atypical femur fractures.

Bisphosphonates are effective in reducing hip and other fractures. However, concerns about atypical femur fractures (AFFs) have contributed to substantially decreased bisphosphonate use, and hip fracture rates may be increasing. Despite this impact, important uncertainties remain regarding AFF risks including the association between bisphosphonate use and other risk factors such as BMD, age, weight, and race. To address this evidence gap, a cohort study of 196,129 women ≥50 years of age in the Southern California Kaiser Permanente HMO women (with ≥1 bisphosphonate prescription) were studied; the primary outcome was radiographically-adjudicated AFF between 2007 and 2017. Risk factors including bisphosphonate use and race were obtained from electronic health records. Multivariable Cox models were used for analysis. Benefit-risk was modeled for 1-10 years of bisphosphonates to compare fractures prevented vs. AFFs associated. Among 196,129 women, 277 (0.1%) sustained AFFs. After multivariable adjustment, AFF risk increased with longer bisphosphonate duration: hazard ratio (HR) increased from HR = 8.9 (95%CI: 2.8,28) for 3-5 years to HR = 43.5 (13.7138.1) for >8 years. Hip BMD, surprisingly, was not associated with AFF risk. Other risk factors included Asian ancestry (HR = 4.8 (3.6, 6.6)), short stature, overweight, and glucocorticoid use. Bisphosphonate discontinuation was associated with rapid decrease in AFF risk. Decreases in osteoporotic and hip fractures risk during 1-10 years of bisphosphonates far outweighed the increase AFF risk in Caucasians, but less so in Asians. In Caucasians, after 3 years 149 hip fractures were prevented with 2 AFFs associated compared to 91 and 8 in Asians. The evidence for several potential mechanisms is summarized with femoral geometry being the most likely to explain AFF risk differences between Asians and Caucasians. The results from this new study add to the evidence base for AFF risk factors and will help inform clinical decision-making for individual patients about initiation and duration of bisphosphonate therapy and drug holidays.

Prebiotic to Improve Calcium Absorption in Postmenopausal Women After Gastric Bypass: A Randomized Controlled Trial.

CONTEXT: The adverse skeletal effects of Roux-en-Y gastric bypass (RYGB) are partly caused by intestinal calcium absorption decline. Prebiotics, such as soluble corn fiber (SCF), augment colonic calcium absorption in healthy individuals. OBJECTIVE: We tested the effects of SCF on fractional calcium absorption (FCA), biochemical parameters, and the fecal microbiome in a post-RYGB population. METHODS: Randomized, double-blind, placebo-controlled trial of 20 postmenopausal women with history of RYGB a mean 5 years prior; a 2-month course of 20 g/day SCF or maltodextrin placebo was taken orally. The main outcome measure was between-group difference in absolute change in FCA (primary outcome) and was measured with a gold standard dual stable isotope method. Other measures included tolerability, adherence, serum calciotropic hormones and bone turnover markers, and fecal microbial composition via 16S rRNA gene sequencing. RESULTS: Mean FCA ± SD at baseline was low at 5.5 ± 5.1%. Comparing SCF to placebo, there was no between-group difference in mean (95% CI) change in FCA (+3.4 [-6.7, +13.6]%), nor in calciotropic hormones or bone turnover markers. The SCF group had a wider variation in FCA change than placebo (SD 13.4% vs 7.0%). Those with greater change in microbial composition following SCF treatment had greater increase in FCA (r2 = 0.72, P = 0.05). SCF adherence was high, and gastrointestinal symptoms were similar between groups. CONCLUSION: No between-group differences were observed in changes in FCA or calciotropic hormones, but wide CIs suggest a variable impact of SCF that may be due to the degree of gut microbiome alteration. Daily SCF consumption was well tolerated. Larger and longer-term studies are warranted.